This invention relates to improved well tools for use in spinning and applying torque to a section of well pipe in connecting it to or disconnecting it from the upper end of a pipe string in a well.
In adding a length of pipe to the upper end of a drill string, or disconnecting a section of pipe from the string, a conventional way of turning one pipe section relative to another is by power derived from a winch or `cathead` of the draw works. The major portion of the rotary motion may be effected by a spinning operation in which a chain wound about a section of the pipe is pulled by the cathead to rapidly spin it. A final torqueing operation or initial joint breaking operation may be effected by a tong pulled by a line wound about the cathead. In lieu of this cathead actuated arrangement, more sophisticated rigs sometimes employ power spinners and torque wrenches which are receivable about the pipe and are adapted to more automatically perform the connecting and disconnecting operations. When such apparatus is employed, the draw works may not include a rotary cathead and consequently if the more sophisticated and automatic equipment becomes inoperative for any reason there may be no back up method of spinning and torqueing the pipe.
In addition to the above discussed types of devices for use in connecting and disconnecting well pipe, there has also been employed in the past a torqueing tool including a power cylinder mounted at a side of a wall and having a piston which acts upon movement relative to the cylinder to exert a pulling force on a line connected to a tong, to thus apply torque to a pipe about which the tong is received. The piston in that prior arrangement carries a sheave about which the pulling lines extends to cause the desired longitudinal displacement of the line in response to piston movement.